TIJUANA  For Victor Ruiz, an unemployed Honduran construction worker with dreams of reaching San Francisco, the first hurdle was making it through Mexico. That meant crossing without permission from Guatemala, enduring a dangerous journey on freight trains to the U.S. border, then hitching a ride from Mexicali to Tijuana.

Ruiz is part of a surge of undocumented Central Americans who have arrived at the U.S. border in recent months, prompting a question: How are so many managing to travel so far to get here?

It has shed a spotlight on Mexico as a corridor for the flow of Hondurans, Salvadorans and Guatemalans fleeing violence and poverty in their countries, especially the unprecedented numbers of unaccompanied minors.

The migrants’ increased presence at the U.S. border — mostly in Texas — has been raising questions about security along Mexico’s southern border, a 750-mile stretch that the country shares with Guatemala and Belize. Border towns there are a launching point for their long and arduous journey to the United States, where evading government checkpoints means they must pass through areas controlled by organized crime.

Last month, Mexican President Enrique Peña Nieto announced a plan aimed gaining greater control on the flow of people entering Mexico while protecting the rights of migrants.

The Southern Border Program pledges upgrades to the 12 border crossings and the establishment of mobile checkpoints to ensure the legal flow of goods and people. It also stresses temporary work and visitor permits allowing citizens of Belize and Guatemala to legally cross to Mexico’s four southern border states.

Miguel Angel Osorio Chong, Mexico’s interior minister, called the program’s July 7 announcement historic. “Incredibly, there has never been discussion of a migration policy for our country’s southern border,” he said in a nationally broadcast radio interview.

Beyond Mexico’s four southern border states, “those who don’t have documents to go further into our territory will be returned to their countries,” Osorio Chong said.

He also announced a crackdown on La Bestia, the informal name for a network of privately operated freight trains that carry many Central American stowaways across Mexico to the U.S. border: “We cannot allow them to run risks, that they continue to lose their lives, without anyone doing anything.”

U.S. officials were quick to praise the measures.

“We applaud yesterday’s announcement,” read a statement from the U.S. Embassy in Mexico City. “The Mexican government has been working on this strategy for more than a year, and has routinely briefed the U.S. government on Mexico’s objectives.”

The U.S. government already has been supporting Mexico’s efforts to increase security on its southern border. Funding has included $6.6 million through the U.S. State Department for non-intrusive inspection equipment and $3.5 million for mobile kiosks that record biometric and biographic data, according to a report by the Congressional Research Service.

Sensitive topic

Immigration policy is a politically sensitive topic in Mexico — but the issues are different than in the United States, where the discussion has focused on the large numbers of undocumented immigrants. In Mexico, guaranteeing the human rights of migrants makes up a big part of the public discourse. Less public — but no less present — are pressures from the United States for greater border security.

“Mexican policy makers today, as has also been the case in the past, are caught between a rock and a hard place,” said Arturo Sarukhan, Mexico’s ambassador to the United States from 2007 until 2013. “Some leaders increasingly understand the importance of enforcing border security yet don’t want to be perceived by Mexican public opinion, whether rightly or wrongly, as doing the dirty work of the ‘gringos,’” he said.

With a long and deeply embedded tradition of emigration to the United States, many Mexicans identify with Central American migrants traveling through their country, said Ernesto Ruffo, a senator from Baja California. “We see them with sympathy, because they have no alternatives in their homes communities. We know that they send back remittances.”

Despite the public sympathy, large numbers of Central Americans are in fact sent back home by the Mexican government, though it’s not clear how many of those are aiming to reach the United States. Last year, Mexico’s National Migration Institute detained 86,298 foreigners, according to figures obtained by Washington Office on Latin America, or WOLA. Of those, 80,079 were deported — the great majority from Honduras, Guatemala and El Salvador.

A WOLA report entitled “Mexico's Other Border” released in June and focusing on Central Americans and Mexico’s southern border found that “these migrants encounter a border security policy that is hard to define, at times contradictory, and unevenly implemented — but clearly toughening, often with U.S. backing.”

2011 immigration law

Mexico enacted an immigration law in 2011 that decriminalized the act of entering Mexico without documents, making it an administrative infraction. Authorities hoped the measure would make migrants less vulnerable both to trafficking organizations and official corruption.

But abuses have continued, migrant advocates say. “Corruption is up to the hilt,” in Mexico’s National Migration Institute, charged the Rev. Alejandro Solalinde, a Catholic priest and well-known human rights activist in Mexico who works with migrants, during an interview last month on Radio Formula. “What are you going to cure, if it’s in a terminal phase, if the infection has reached the marrow?”

That prompted a written response from the institute, asking for help in identifying corrupt officials, pledging to combat corruption and saying that since Peña Nieto’s term began last year, the agency has been engaged in an “unprecedented effort ... mainly to carry out a profound cleansing of the cancer that for many years cast shame on this institution.”

Doris Meissner, a senior fellow at the Migration Policy Institute in Washington, D.C. , said controlling the southern border won’t be easy. “The big challenge is that it’s a big distance, a lot of unsettled territory,” said Meissner, former commissioner of the U.S. Immigration and Naturalization Service. “It’s going to take a lot of money, public funds to develop it effectively. They’re going to need to be able to hire and train professional law enforcement people and really combat corruption because border enforcement is always classically subject to corruption.”

Everard Meade, director of the Trans-Border Institute at the University of San Diego, said that the new measures are not likely to decrease the flow of Central Americans coming through Mexico. “They’ve done periodic sweeps over the years,” Meade said. “It hasn’t lessened the flow. What we do know is that it has gotten a lot more dangerous.”

For both Mexico and the United States, the solution rests in working with the Central American countries to address the root causes of the migration, said Manuel Angel Castillo, an immigration scholar at the Colegio de Mexico in Mexico City. Mexico “cannot stop something that originated elsewhere,” he said.

As north-bound Central Americans continue to pass through Mexico, “the challenge is how find a coherent formula that enforces the law at the same time protects human rights,” Castillo said. “There is no easy formula.”

So far, there have been few tangible effects of the new policy. But as Mexico’s National Migration Institute has begun cracking down on the illicit freight train riders, migrant advocates have been raising their voices in protest. In Huixtla, Chiapas, last week, a Catholic priest publicly denounced a raid he said was conducted by Mexican immigration agents and masked civilians to prevent migrants from boarding a freight train.